def get_max_length(values):
""" Returns the maximum length value of the input. If
no values found besides unknown it will just return 'None'
Inputs:
- dictionary or list of string values
Outputs:
- the single maximum value
"""
max_length = 0
for value in values:
if not typer.is_unknown(value):
if len(value) > max_length:
max_length = len(value)
return max_length